1. Technical Field
The present invention relates to a method and an apparatus of measuring a relative phase of a bio-cell or bio-cells, more particularly, relates to a method and an apparatus of measuring a relative phase of a bio-cell, for making an image of the bio-cell by measuring its polarization state and relative phases.
2. Background Art
As observing bio-cells in real time conventionally is getting important in view of mobility, drug reaction, division property and the like of the bio-cells, researches for the real-time observation without pre-processing are ongoing, instead of performing an irreversible bio-chemical process like dyeing. Namely, in these days, the technologies of cell detection that are enable observing and re-measuring cells without destructive process attract great attention.
To observe cell tissue as a specimen without destruction, an optical microscope may be used for the observation of biological sample, such as bio-cell. However, since many of the bio-cells are substantially invisible with the naked eye, it is difficult to observe the bio-cells in that any absorption of the light does not occur.
Accordingly, conventionally developed are a phase-contrast microscope and a DIC microscope, in order to observe the bio-cells in visible area.
At first, the phase contrast microscope is a microscope that uses the difference of the refractive index, unlike the usual optical microscope, to display the difference of the contrast using the interference between the diffracted ray and not-diffracted ray.
Otherwise, the DIC microscope is a microscope that uses the natural phenomenon that the light speed is decreased in a material to display the interference between a light passing through a sample and a light well-separated from a light source.
The above mentioned phase contrast microscope and interference microscope make it possible to observe the biological sample, like a bio-cell, that is invisible through the conventional optical microscope, however, since they just provide qualitative phase information, the precise interpretation to the biological sample easily reaches the limit. Thus, it is necessary to develop apparatuses or devices that can provide quantitative phase information about the biological sample.
To develop microscopy technology, a method of imaging quantitative phase information of the biological sample is being studied. For example, an imaging device that measures the bio-cell's phase and birefringence using OCT (Optical Coherent Tomography) to calculate the quantitative phase information and make an image of inside of the sample, is developed, however, in spite of its slow detection speed, it needs a high-speed scanning device, has a difficulty to observe the bio-cell in real time, and produces a noisy sound.